Proponents of net neutrality are pursuing several different paths to prevent internet service providers from tampering with website access.

Federal regulators may have opted to toss net neutrality rules last month, but opponents of the repeal are looking to extend the fight for a free and open internet well into the new year.

On Dec. 14, the Federal Communications Commission passed the Restoring Internet Freedom order in a 3-to-2 party-line vote, dismantling the regulatory framework that prevented internet services from speeding up, slowing down or blocking access to certain websites.

While FCC Chairman Ajit Pai argues the measure will increase competition among broadband providers and spur infrastructure investment, others say the rules are necessary for maintaining freedom and competition online.

As officials put the finishing touches on the controversial proposal, lawmakers and open internet advocates are mounting a number of legislative and legal efforts to keep net neutrality on the books.

“Without strong net neutrality rules, entrepreneurs, inventors, small businesses, activists and all those who rely on a free and open internet will be at the mercy of big broadband companies,” said Sen. Ed Markey, D-Mass., in a statement after the vote. “We will fight the FCC’s decisions in the courts, and we will fight it in the halls of Congress.”

One of the most outspoken supporters of net neutrality on Capitol Hill, Markey is spearheading an effort to overturn the FCC’s “misguided and partisan” decision using the Congressional Review Act. The day of the commission’s vote, he announced plans to introduce a joint resolution that would undo the repeal and reinstate open internet rules.

Though Markey cannot formally introduce the resolution until 20 days after the order is published in the Federal Register, 28 Democratic senators have pledged to support the bill so far. Adding one more cosponsor would force a vote on the Senate floor.

But Republicans lawmakers, who largely favor internet deregulation, are steering clear of the joint resolution and instead offering their own plans to protect net neutrality. The Open Internet Preservation Act, introduced by Rep. Marsha Blackburn, R-Tenn., would bar internet service providers from blocking or slowing legal web traffic, but allow them to charge for faster speeds.

A large number of net neutrality advocates remain unappeased by Blackburn’s “light-touch” approach, which fails to address their key concerns about internet service providers prioritizing certain sites over others. Allowing fast and slow lanes “would permanently undermine the free and open internet,” said Markey.

The Internet Association, a trade group that represents tech titans like Google, Facebook and Amazon, said the bill failed to “meet criteria for basic net neutrality regulation,” but commended Blackburn for moving the conversation forward.

While lawmakers battle over net neutrality on Capitol Hill, advocacy organizations and state attorney generals are taking the fight to the courtroom.

“We think [the FCC] action was unlawful for several reasons, both in terms of substantive law and in terms of procedure,” said John Bergmayer, senior counsel for the open internet group Public Knowledge, in a conversation with Nextgov.

Public Knowledge is one of the many advocacy groups that have called into question the FCC’s handling of public feedback on net neutrality and pointed out unanswered legal concerns within the order itself. Bergmayer said the FCC dismissed many opposing arguments and data without any clear reasoning, and the agency received public input on critical aspects of the order like the overruling of state net neutrality laws.

Researchers also disputed the integrity of the public comment process after determining that millions of submissions in favor of the repeal were likely generated by spambots. While Bergmayer noted the sheer numbers shouldn’t necessarily affect the final say on net neutrality, the findings undermine confidence in agency’s procedure.

“The FCC process is totally compromised,” Bergmayer said. “It definitely makes their process look bad, not only when people can file these fraudulent comments, but they really have no way of taking fraudulent comments out.”

An investigation by New York Attorney General Eric Schneiderman also found that 2 million commenters used stolen identities of real Americans, violating New York state law. He’s now leading a multi-state lawsuit to hold the FCC accountable for a “deeply corrupted” public comment process.

“The FCC’s decision to go ahead with the vote makes a mockery of government integrity and rewards the very perpetrators who scammed the system to advance their own agenda,” Schneiderman said in a statement.